Traumatic head injury is the leading cause of mortality and morbidity in previously healthy young people and represents a major health and economic problem. The aims of this study are to determine the neuropsychological, psychosocial and emotional consequences of head injury; examine the recovery from such deficits; and investigate the utility of head injury severity indices and risk factors in predicting long-term behavioral outcome. A major emphasis of this study is to improve prediction by considering, in addition to head injury severity level, other risk factors such as pre-exist central nervous system dysfunction, social support available to the individual, as well as the individual's emotional status. In addition, previously obtained results concerning prediction of outcome and the validity of modifications to the Sickness Impact Profile will be cross-validated. This study will follow head injured patients of varying severity with and without pre-existing conditions, in order to closely examine outcome at one and 12 months post injury in the areas of neuropsychological and psychosocial functioning. These patients will be compared to an uninjured group similar in age, education, sex, and pre-existing conditions. The head injured patients will be evaluated at fixed times during the first week post injury by means of the Glasgow Coma Scale and a brief neurological examination. There are several long-term objectives of this study which include better delineation of which deficits are related to the head injury versus which are pre-existing; development of appropriate treatment programs on the basis of improved understanding of the nature of these difficulties; identifying and providing treatment to patients who need it as opposed to patients who will improve with or without it; and improvement in the efficiency of treatment studies by developing prediction equations.